Being locked into the grey interface feels confining & claustrophobic. Not being able to resize your windows with a minimize button too is not such a great feature. The speed is very good, fast & fluid with the smudge tool, and saving in the bkgd is great too. More to test would be nice to get more time with the beta than 7 days on it. I also got a warning fbox that said "Photoshop detacted graphicshardware that is not officially supported. If you experience problems please uncheck the Use Graphics Processor checkbox in the Performance panel of the Preferences dialog." I guess this meands my Grahics card might not be up to speed with it? I'm on an older iMac late 2006 model, with these specs for the graphics card.
Chipset Model: ATY,RadeonX1600
PCIe Lane Width: x16
VRAM (Total): 128 MB
Resolution: 1680 x 1050
Pixel Depth: 32-Bit Color (ARGB8888)
Model Name: iMac
Model Identifier: iMac5,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.16 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 3 GB
Bus Speed: 667 MHz
So far no real probelms it seems but I guess there could be berter perfomance & speed?
Should I uncheck the Use graphics Processor checkbox?
It looks like you are using an older system, 32 bit, with an unsupported video card.
See this link for an explanation of which operating systems are supported. 32 bit on the MAC is no longer supported.
You can check these links to see what video cards are supported and system requirements: